Air conditioning of a weaving machine with displacement type air flow stream

ABSTRACT

A process for the air conditioning of a weaving machine includes generating, for the weaving machine, at least one conditioning air stream spaced from a warp of the weaving machine and directed towards the warp, and distributing the conditioning air stream in stages so as to form a downwardly directed displacement-type flow towards threads of the warp. The displacement-type flow is a non-turbulent, uniform flow over a cross-sectional profile of the flow.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a process for the air conditioning of a weavingmachine, and more particularly to a device for the air conditioning aweaving machine.

2. Related Art

With the objective of reducing the interruptions of operation ofpowerful weaving machines, which interruptions result mainly from threadbreakages, attempts have been made for a relatively long time tooptimize the weaving conditions. Endeavours to achieve this objectivejust by influencing the space air conditioning of a weaving machine roomresult in a large volume flow of air, with a large power requirement permachine.

However, in connection with dust removal, processes are also known bywhich the climate directly at the weaving machine is influenced. In aknown process of this type, conditioned air is supplied both via ceilingoutlets distributed within the room and also through local outlets. Inthis case, for each machine a local outlet is provided, which exhibits aslot-shaped exit opening at a spacing above the warp. In another knownprocess, the local outlets are disposed below the warps. In both cases,the exit opening extends approximately transversely to the warp over itsfull width and releases a jet of conditioned air, which jet is directedtowards the warp.

In a report entitled "Weaving machine dust removal and air conditioningof a weaving machine--a conflict?" (Dr.-Ing. Helmut Weinsdorfer,Dipl.-Ing. Ulrich Stark), presented on the occasion of the 6th WeavingIndustry Colloquium (16/17 October 1990) and published by the Institutefor Textile and Process Technology, 7306 Denkendorf, Germany, anexperimental arrangement is described which exhibits a local outlet ofthe above type, which outlet is directed vertically from above onto theback shed.

In the majority of cases, the air conditioning of the machine usinglocal outlets brings, related to the frequency of thread breakage, amarked improvement as compared with applications in which an influenceis exerted on the humidity conditions at the weaving machine only viathe space air conditioning. In addition to this, there is also aconsiderably lower power requirement. However, in order to achievesatisfactory results it is still necessary to generate considerablevolume flows of air, and as far as the operating costs are concerned theincreased maintenance effort for the cleaning of the local outlets isalso significant.

SUMMARY OF THE INVENTION

The object of the invention is to provide a process which brings aneffective conditioning with a considerable reduction of the airconditioning costs per weaving machine by reduced power requirement andvolume flow of air as well as lower water consumption, without creatingan impermissible obstruction in visual terms or for accessibility.

In the present context, a piston-type displacement flow is understood asreferring to a low-turbulence flow with a distribution which isapproximately uniform over its full cross section and approximatelyequal velocity. In this case, exit velocities between 0.3 and 1.2 m/secenter into consideration.

The invention is based on the finding that the transport of the moistureby an air jet blown out from a slot-shaped exit opening is of loweffectiveness and is therefore uneconomical. What is responsible forthis is mainly the relatively high exit velocity which is required forthe throughput of the required quantity of air. Investigationsdemonstrate that in the first instance a considerable part of theconditioning air blown out does not reach the (still noninterwoven) warpthreads. Subsequently, a part of this air rebounds at the warp, withoutbeing able to give off its humidity. This means that considerably moreconditioned air must be conveyed than comes into action at the warp toachieve the relative humidity aimed at.

The displacement flow employed according to the invention permits aquite considerable reduction of the required exit velocity as comparedwith that from a slot-shaped exit opening, with an equal path to betraversed to reach the warp.

By virtue of the displacement flow which is in practice compact butwhich impinges on the warp at a low velocity, this flow does notrebound, but is mainly deflected. This deflection takes place gently andwhile preserving the piston-type nature, in order to flow away along thewarp threads, mainly in the direction of the warp beam. This gives anoptimal utilization of the conditioning air and it becomes possible toinfluence directly the humidity of the warp threads themselves, in orderto condition these for the subsequent processing. With relatively smallquantities of air and a low water requirement, optimal humidity is thuscreated directly at the warp, and the latter is kept to a high degreedust-free. Accordingly, the air conditioning costs may be considerablyreduced.

As a result of the particular properties of the piston-type displacementflow, only a negligible quantity of surrounding air is set into motionby inductive means. Consequently, virtually no transport of suchsurrounding air in the direction of the warp is initiated. This is ofimportance in circumstances in which the relative humidity in theweaving room is considerably below the optimal values and can counteractthe positive influence of the conditioning air at the warp.

The piston-type displacement flow permits the creation and maintenance,within its cross section, of conditions which are different from thoseof the surroundings. By designing the cross sectional shape anddimensions, it is accordingly possible to control the climate of eachrespective zone at a textile machine with respect to requiredproperties. The entry of entrained matter and dust from the surroundingsinto this zone is likewise prevented. If this is required, it isaccordingly also possible to control at a machine or within the deliveryregion of the textile material, a plurality of zones, by a respectivepiston-type displacement flow; in this case, the climatic conditions inthese zones can be designed to be different. Accordingly, piston-typedisplacement flows may be employed with advantage also 10 for the airconditioning of other textile procedures and processes such as forexample in carding, in depositing, storage and take-up of the slubbingfrom the can, in stretching and spinning, as well as in twisting.

The experience gained in the application of the process according to theinvention as well as in the operation of the device which is likewiseaccording to the invention has shown that the avoidance of thecirculation of surrounding air also has a beneficial effect in the senseof the reduction of the maintenance expenditure, especially with regardto cleaning in the region of the local outlets.

BRIEF DESCRIPTION OF THE DRAWINGS

The process according to the invention and the device according to theinvention are explained in greater detail hereinbelow with reference toan illustrative embodiment relating to the air conditioning of a weavingmachine as well as with reference to the drawing. In the drawing:

FIG. 1 diagrammatically shows the conditions at a weaving machineequipped with a device according to the invention, in the application ofan embodiment of the process;

FIG. 2 shows a vertical cross section along line II--II in FIG. 3,through the local outlet of the device according to FIG. 1, which localoutlet is shown on an enlarged scale, and

FIG. 3 shows a bottom plan view of the local outlet according to FIGS. 1and 2, partly broken away.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EXEMPLARY EMBODIMENT

In FIG. 1, reference numeral 2 generally designates a weaving machinehaving a warp beam 4, thread stop motions 6, a heald frame assembly 8, aslay 10, and a cloth beam 12. The warp threads which pass over abackrest 14 and which form the warp 16 are designated by 18 and the backshed of the shed adjoining the thread stop motions 6 is indicated at 20.

In the illustrative embodiment shown, a local outlet 22 is disposedabove the weaving machine 2 and at a spacing from the warp 16 or theback shed 20, which local outlet is supplied with conditioned air via aline 24 from an air conditioning plant 26. The local outlets of allfurther weaving machines of the weaving room (not shown) are alsoconnected to the same air conditioning plant 26. The local outlet 22possesses an exit opening 32 directed downwards towards the warp 16 andextends horizontally over the entire working width of the weavingmachine 2; in this case, the exit opening is directed approximately atright angles to the general extent of the warp. The design of the localoutlet is evident from FIGS. 2 and 3.

As may be inferred from the cross sectional representation of FIG. 2,the local outlet 22 comprises a box 30 of elongate form with uniformrectangular cross section over its longitudinal extent. The box 30 isclosed on all sides with the exception of the bottom surface forming theexit opening 32. At the top surface 34 of the box 30 there is provided,approximately at the longitudinal center thereof, a cylindricalconnecting piece 36 for connection with the line 24, which connectingpiece is connected with the inner space 40 of the box via a circularinlet opening 38 (shown in broken lines in FIG. 3) of the same internalcross section. The bottom surface and the top surface represent the longsides of the rectangular cross sectional shape of the box.

The inner space 40 contains distribution components to distributeuniformly the air flowing in through the inlet opening 38 over thesurface of the exit opening 32 and to generate the displacement flowwhich is provided according to the invention. These distributioncomponents comprise, seen in the direction of flow, a perforated sheet42 which extends parallel to the top surface 34, but at a spacing fromthe latter, over a central longitudinal region and the full width of theinner space 40. Thus, the distribution components are stacked in spacedrelation in the direction of air flow. The length of the perforatedsheet 42 secured by means of bolts 44 to the top surface 34 of the box30 is greater than the diameter of the inlet opening 38, but smallerthan the length of the inner space. Below the perforated sheet 42 thereextends, likewise parallel to the top surface 34 over the full width ofthe inner space 40, a further perforated sheet 46, which is secured tothe side walls of the box 30 or is supported in an appropriate manner onthe bottom surface. In the longitudinal direction of the inner space 40the extent of this perforated sheet 46 is restricted to an amount whichis somewhat smaller than the diameter of the inlet opening 38. Thepassage cross section formed by the perforating of the perforated sheets42 and 46 accounts for preferably between 35 and 45%, related to thesurface area thereof.

There finally follows, as the last distribution component in the innerspace 40 of the box, an air-permeable mat 48, for example of anappropriate foam material, which mat is clamped between a peripheralflange 58 of the box and a grid 50. Mat 48 and grid 50 extend over thefull length and width of the inner space. The grid 50, which is formed,for example, by a wire grid of relatively large mesh width, is supportedon a narrow frame 52, which is provided at the bottom surface of thebox. The frame 52 limits the exit opening 32 by the length 54 and thewidth 56. Preferably, the mat 48 is fitted in the box for example bydemountability of the frame 52, so that its accessibility for thepurpose of exchange is possible at any time. A foam material with apressure loss of 15-20 Pa at 0.6 m/sec has proved to be suitable for themat 48.

Together with the distribution components 42, 46 and 48, the box 30represents an air distributor 60. The described design and arrangementof the distribution components in this box give a distribution of theair in stages flowing in through the inlet opening 38 into the innerspace 40. As a result of the perforated sheet 42, which, also acting asbaffle plate, lies opposite the inlet opening, only a part of this aircan pass through in the direction of the arrows 62, while the remainderis deflected to opposite sides in the longitudinal direction of theinner space 40 with low pressure loss, without having to overcome animpediment to flow on the further path to the mat 48, i.e. in thedirection of the arrows 64. In order to reduce the velocity in thepartial stream flowing without deflection in the direction of the arrows62, this partial stream must still overcome the perforated sheet 46. Thepartial streams 62 and 64 thus arrive at approximately the same velocityat the mat 48. Besides a further balancing, a fine distribution of theair takes place at the mat 48 and upon passing through the latter apiston-type displacement flow formed of the finest stream lines iscreated. For the outlet velocity, in the present context a restrictionto values of between 0.5 and 0.8 m/sec is appropriate. Thus, thequantities of air may be designed to be different, within certainlimits, even in the case of the same dimensions of the air distributor60.

In operation, the air conditioning plant delivers conditioned air, whichemerges from the local outlet 22 (FIG. 1) formed by the air distributor60, as a piston-type displacement flow 70, e.g. with an outlet velocityof 0.6 m/sec vertically downwards and in this case exhibits a width offor example 300 mm, depending upon the dimension 56. The displacementflow traverses the distance, amounting for example to 0.9 m, to theupper group of warp threads 20' of the shed 20 in compact form, andimpinges on said group upstream of the heald frame assembly 8. Uponimpinging on said group as well as on the lower group of warp threads20", the air is deflected at least as the major partial stream 72towards the thread stop motions 6 and flows along the warp threads 18counter to their direction of delivery. A partial stream 74 flows in theshed region along the corresponding warp threads and flows awaydownwards between these. In this case, both partial streams of this aircreate in the environment of the warp 16 a climate which is suitable forthe transport and the processing, in that heat and dust are conductedaway and the relative humidity is kept at an advantageous value. Sincethe warp threads 18 are circumcirculated by the stream over a relativelylong period of time, a direct moisture takeup also takes place, whichhas a favorable effect both for the weaving process and also for thewater consumption. In particular, this applies to the influence of thepartial stream 72, which flows along the warp threads, envelops theseand screens them off in relation to the surrounding air.

A spacing of approximately 1.2 m of the local outlet from the warprunning therebelow represents an upper limit on economical grounds.

It should be added that below the weaving machine 2, expediently in amanner known per se, a floor opening 80 is provided, via whichdust-laden air is transported away.

It has proved to be the case that the arrangement of the local outlet 22so that the displacement flow 70 impinges on the upper group of warpthreads 20' at an acute angle greatly favors the deflection of the sameor the formation of a relatively large partial stream 72 and anorientation of the same parallel to the warp threads. Since an effectiveconditioning of the warp threads 18 can be achieved only over asufficiently long period of action, this partial stream acts as its ownconditioning medium. With the objective of a long period of action ofthe air streams 70 and 72 respectively, the arrangement of the airoutlet 22 so that the stream 70 impinges on the warp 16 or the back shed20 directly behind the heald frame assembly 8 is advantageous. On theother hand, in the case of such an arrangement an air build-up takesplace at that side of the heald frame assembly which faces the back shed20, which air build-up assists the deflection of the partial stream 72.

Where the conditioning is also to take place in the region of the frontshed or of the gate for the weft thread spools, according to theinvention additional outlets similar to the local outlet 22 are to beprovided for this purpose, which additional outlets are supplied fromthe air conditioning plant 26. Just like the local outlet 22, theseoutlets are also to be provided in the form of elements separate fromthe weaving machine.

We claim:
 1. A process for the air conditioning of a weaving machine,comprising the steps of:generating, for the weaving machine, at leastone conditioning air stream spaced from a warp of the weaving machineand directed towards the warp, and distributing the conditioning airstream in stages so as to form a downwardly directed displacement-typeflow towards threads of the warp, said displacement-type flow being anon-turbulent, uniform flow over a cross-sectional profile of the flow.2. The process as claimed in claim 1, further comprising the step ofconditioning the warp threads by a partial stream of the displacementflow, the partial stream flowing along the warp threads.
 3. The processas claimed in claim 1, further comprising the step of deflecting thedisplacement flow directed onto a back shed of the weaving machine andthen guiding the displacement flow along the warp threads in a directionof a side of a warp beam of the weaving machine.
 4. The process asclaimed in one of claims 1, 2 or 3, wherein a maximum outlet velocity of0.9 m/sec is imparted to the displacement flow.
 5. A device for airconditioning a weaving machine comprising:at least one local air outletfor the weaving machine, said outlet being cooperable with an inletopening to an air conditioning plant and being constructed and arrangedto generate an air stream directed downwards into a region of a warp ofthe weaving machine, wherein an outlet opening of the air outlet isconstructed and arranged to extend transversely to the warp and to bespaced from the warp, an air distributor being connected upstream of theoutlet opening, said air distributor including a plurality of flatdistribution components stacked in a spaced relation in the direction ofair flow, said flat distribution components being constructed andarranged to distribute air between the inlet opening and the outletopening, and wherein the outlet opening exhibits a width of at least 150min.
 6. The device as claimed in claim 5, wherein the outlet opening ofthe air outlet is provided at a long side of a box, which forms the airdistributor and which is approximately rectangular in profile and havinga cross section which approximately corresponds to the cross section ofthe outlet opening.
 7. The device as claimed in claim 5 or 6, whereinthe distribution components comprise an air-permeable mat and aperforated sheet, andwherein a further distribution component disposedopposite the inlet opening is provided as a baffle component in the airdistributor.
 8. The device as claimed in claim 7, wherein the perforatedsheet is disposed, in a direction of flow, upstream of the mat andparallel thereto and to the outlet opening and a surface extent of themat is approximately the same as the cross section of the outletopening.
 9. The device as claimed in claim 5 or 6, wherein the airdistributor includes at least one lateral outlet opening.
 10. Anarrangement for air conditioning a textile machine, comprising:a weavingmachine, a local flow outlet disposed above the weaving machine and inflow communication therewith, said outlet being constructed and arrangedto produce an air flow stream having a uniform distribution in stagesover a cross sectional profile of the flow such that a flow velocity isconstant over said cross sectional profile and said outlet having anelongated exit opening.
 11. The arrangement according to claim 10,wherein said exit opening extends substantially along an entire workinglength of the weaving machine.
 12. A device for air conditioning aweaving machine comprising:at least one local air outlet for the weavingmachine, said outlet being connected via an inlet opening to an airconditioning plant and being constructed and arranged to generate an airstream directed downwards into a region of a warp of the weavingmachine, wherein an outlet opening of the air outlet is constructed andarranged to extend transversely to the warp and to be spaced from thewarp, an air distributor being connected upstream of the outlet opening,said air distributor including a plurality of flat distributioncomponents connected in series in the direction of air flow, and whereinthe outlet opening exhibits a width of at least 150 mm, and wherein theoutlet opening of the air outlet is provided at a long side of a box,which forms the air distributor and which is approximately rectangularin profile and having a cross section which approximately corresponds tothe cross section of the outlet opening.
 13. The device as claimed inclaim 12, wherein the distribution components comprise an air-permeablemat and a perforated sheet, andwherein a further distribution componentdisposed opposite the inlet opening is provided as a baffle component inthe air distributor.
 14. The device as claimed in claim 13, wherein theperforated sheet is disposed, in a direction of flow, upstream of themat and parallel thereto and to the outlet opening and a surface extentof the mat is approximately the same as the cross section of the outletopening.
 15. The device as claimed in 12, wherein the air distributorincludes at least one lateral outlet opening.
 16. A process for the airconditioning of a weaving machine, comprising the steps of:generating,for the weaving machine, at least one conditioning air stream spacedfrom a warp of the weaving machine and directed towards the warp,distributing the conditioning air stream so as to form a downwardlydirected piston-type displacement flow towards threads of the warp, anddeflecting the displacement flow directed onto a back shed of theweaving machine and then guiding the displacement flow along the warpthreads in a direction of a side of a warp beam of the weaving machine.17. A process for the air conditioning of a weaving machine, comprisingthe steps of:generating, for the weaving machine, at least oneconditioning air stream spaced from a warp of the weaving machine anddirected towards the warp, and distributing the conditioning air streamso as to form a downwardly directed piston-type displacement flowtowards threads of the warp, wherein a maximum outlet velocity of 0.9mm/sec is imparted to the displacement flow.
 18. A process for the airconditioning of a weaving machine, comprising the steps of:generating,for the weaving machine, at least one conditioning air stream spacedfrom a warp of the weaving machine and directed towards the warp,distributing the conditioning air stream so as to form a downwardlydirected piston-type displacement flow towards threads of the warp, andconditioning the warp threads by a partial stream of the displacementflow, the partial stream flowing along the warp threads, wherein amaximum outlet velocity of 0.9 mm/sec is imparted to the displacementflow.
 19. A process for the air conditioning of a weaving machine,comprising the steps of:generating, for the weaving machine, at leastone conditioning air stream spaced from a warp of the weaving machineand directed towards the warp, distributing the conditioning air streamso as to form a downwardly directed piston-type displacement flowtowards threads of the warp, and deflecting the displacement flowdirected onto a back shed of the weaving machine and then guiding thedisplacement flow along the warp threads in a direction of a side of awarp beam of the weaving machine, wherein a maximum outlet velocity of0.9 mm/sec is imparted to the displacement flow.